Separating liquids of different specific gravity and means therefor



Nov. 6, 1928. Y

W. G. GUP. LUMSDEN SEPARATING LIQUIDS OF DIFFERENT SPECIFIC GRAVITY AND MEANS THEREFOR 2 Sheets-Sheet 1 Filed Marqh 31. 1926 rzzz-E Q 3 57.12122: h W; N l

Jim IN Zk'n'elwrpdem I $0126 $rd0/L fl 7702mm Nov. 6, 1928. 1,690,741

w. G. G. P. LUMSDEN SEPARATING LIQUIDS OF DIFFERENT SPECIFIC GRAVITY AND MEANS THEREFOR Filed March 31, 1926 2 Sheets-Sheet 2 ,EZLQQZ.

[in 351N 03.- age gain Erie landm- J11 TQRNEK Patented Nov. 6, 1928.

'UNITED'STATES PATENT OFFICE.

WILLIAM GEORGE GORDON PIRIE LUMSDEN, OF LONDON, ENGLAND, ASSIGN OR TO ROD- WAY STEPHENS, LZQUIDATOR OF THE PERBRIGHT COMPANY LIMITED, (IN LIQUI- DATION), OF LONDON, ENGLAND. 1

SEPARA'IING LIQUIDS OE DIFFERENT Application filed March 31, 1926, Serial No.

The present invention relates to separating liquids of different specific gravity and means therefor. v

The present invention being suited for use in separating oil from water such as for example when cleaning out the bilges and tanks of oil burning or oil carrying ships it will be hereinafter described with that application more particularly in view, although it is to be, understood to be applicable to anydiquids of diiferent specific gravity adapted to be separated thereby and whether used on board ship or any floating support or on land.

The invention is applicable to gravity separators in general, and is suited to apparatus of the kind in which the mixed liquid is caused to flow in substantially horizontal direction in a vessel of horizontally elongated form for a time sufficient to enable the lighter liquid to rise, and the lighter liquid is collected inthe upper portion of the apparatus which is provided with a valve, actuated by the abscence or presence of such lighter liquid. through whichsuch lighter liquid is expelled by reason of the pressure maintained on the mass of liquid.

In general, for ordinary cases, it is found advantageous in such apparatus to employ baflies or plates substantially perpendicular to the direction of flow of the liquid, and these plates are usually arranged so that there are only comparatively narrow passages at the top and bottom of the vessel for the flow of the liquids, the general body of the liquid flowing in one direction and the lighter liquid flowing or tending to flow in a contrary direction after rising to the surface As conducing to such contra-flow the top of the vessel is usually sloped appropriately up or down to the collecting head.

While apparatus of the foregoing kind works well for many separations, it is'open to objection in certain cases, for example, when dealing with oil of a mobile nature, the water tending particularly to carry over numerous small particles of oil, sometimes called oil dust, of negligible flotation power which elude gravity separation.

Now, the Object of the present invention is to obviate this disadvantage by causing the small particles to coalesce 1nto drops or SPECIFIC GRAVITY AND MEANS THEREFOR.

98,840, and in Great Britain April 8, 1925.

blobs of a size well adapted for gravity separation.

According to this invention there is provided a method of separating liquids of different gravity consisting in distributing the mixed liquids over a large wetted surface area so as to cause the particles of oil of negligible flotation power to. coalesce for subsequent gravity separation.

By the present invention there is interposed in the flow of the mixed liquid means for causing the particles of negligible fiotaloaded or oil charged material functions as coalescing means causing the small particles of oil, or oil dust, to coalesce in the form of drops or blobs readily capable of gravity separation.

Cow-hair employed in the form of commercial cow-hair felt is found to serve well for the purposes of the present invention, and in one experimental example the actual form was a coarse textile of jute or like with cow-hair through the meshes and felted on both sides, the total thickness uncompressed being from 4; (oneeighth of an inch) to (half an inch) or thereabouts.

Such a mat of commercial cow-hair felt was used on a perforated metal backing presented to the inflow so as to temper any undue forceful impulse.

The mator felting maybe used in various filter-partitioning figurings, as flat, cylindrical, conical, bag, stocking or other forms interposed between the inflow andoutflow of the coalescing system. a v

,Any such forms make convenient units for building up coalescing masses or groups, the principle of divided-flow preferably stepping in to associate a relatively large through-put with a distribution ofthesmall equivalent 7*.

particles evenly over large surface area.

Outflow from the coalescing system should be steadily orderedso as not to tend to again break down or reduce the size of the coalesced particles.

In relation to gravity separation broadly considered, the present invention includes the use of a filter, fwhen spent, as coalescing? means.

The accompanying drawings show by way of example the present invention applied to a gravity separator'of the kind hereinbetore referred to. I p, In the drawings, Figs. 1,2 and 3 are diagrammatic views offorms of apparatus having coalescing means; while Figs. 4 and 5 show two forms of coalescing means suited for carrying out the presentinvention. I In Fig. 1, a vessel 1 of horizontally elongated form is the primary separator. .The mixed liquid enters this vessel 1 at 2. Bafrfles may be provided in the vessel 1. As the mixture flows therethrough the. bulk of the lighterliquid rises and flows backward along the top to a collecting compartment 3. This collecting compartment 3 has a discharge valve 3'" which valve maybe an automatically operated valve comprising a valve proper, a float, and a lever connection between the valve and the float. f j

The heavier liquid with any oil dust is discharged fro m the vessel 1 at l'into a coalescing apparatus 5.

From this coalescing apparatus 5 the final fiow is through the secondaryvessel or separator 6, which may have bafiies 7. During this final flow the coalesced drops or blobs readily rise and pass .tothe collecting compartment 3 through a connectingpipe or the Theheavier liquid discharge is at .8. i

Fig. 2 is similar to Fig. 1, but with the secondary vesselor separator on top of the primary vessel or separator."

The secondary vessel 6.1nay have its own lighter liquid collecting chamber.

Fig. 3 shows an arrangement with the secondary vessel 6 on top of the main vessel 1, the flow from the coalescing apparatus 5 being by way of a trunk or the equivalent '9.

The lighter liquid from this vessel 6 passes to the collecting compartment 3, by way of an opening 10. 11 indicates a guiding baflie ad- ]acent the inlet 2.

Fig. 4 shows by way of example, one form of coalescing apparatus 12, having a divided flow, the inlet being at 13 and the outletat 1 1, the flow being divided up between various filtering components. Each component 15 may comprise a filter pad of cow-hair on a fenestrated or reticulated support or backing. The type of apparatus-shown by Fig. 4 is for a large through-put. i'

' space between Fig. 5 shows acoalescing apparatus 16 for inoroughly soak the cow-hair medium in medium has absorbed its maximum ofoil,

the oil dust is then forced through the me dium with the water and emerges from the medium, not as oil dust, but as drops or blobs oi oil of appreciable dimensions and having considerable flotation, so that the separation q of this oil from the water becomes one of gravity separation. V

The example of apparatus described and shewn is a closed system from inlet to outlet,

that is to say, the coalescing action takes a simple place unexposed to air and the flow of the mixed liquid through the coalescor is apressure flow. y Further in the example described and illustrated the oil and water mixture has only a l 7 short traverse through a pad,.and this arrangement avoids'creating' an excessive back pressure and prevents any. of the accumulated oil from being again emulsified by the searching water flow of th'ehigh throughput. q r

With apparatus according to the present invention the overall dimensions are considerably reduced, for example, the total length of a form of apparatusaccording to Fig. 1 l

I is 23 ft. 9 inches, this being made up as follows, primaryseparatingchamber let it,

primary and second aryseparating chamber 3ft. 9 inches and'secondary I separatingchamber 6 ft. The'di mensions of a separator of design as shown in Fig. l but without the eoalescor would be 40 ft. in length and in addition a filter would be required to ensure a discharge of the heavier liquid free from oil. This saving. in space is of extreme I value especially on board'ship;

The present invention is suited to gravity separators of any type, and particularly separators for oil and water." The means at present adopted to minimize the discharge of elusive oil dust or niggers comprisein some cases excessive dimens ons of the separater; compl cated battles, and chamber arrangements, andin all cases the provision of a filter. By means of the coalescor the dimensions of a separator are reduced, compl ca Vfhat I claim is l H 1. A system for separating liquids of diferent gravity, comprising. a horizontally elongated separating chamber in which as themixture flows therethroug'h'the greater part of the lighter liquid rises, a collectingtions are removed and no filter is necessary.

compartment for said lighter liquid, a discharge valve in said collecting-compartment, a coalescor into which the contaminated heavier liquid enters when discharged from said separating chamber, and in which the very small particles of the lighter liquid coalesce to form drops, a second separating chamber receiving the flow from said coalescor, and means between the first and second separating chambers to allow the lighter liquid from said second chamber to pass to the collecting compartment in said first chamher.

2. A system for separating liquids of different gravity comprising two separating chambers in a single unitary tank, a common lighter liquid collecting chamber, and a co alescor interposed between said separating chambers.

In testimony whereof, I aflix my signature.

WILLIAM GEORGE GORDON PlRlE LUMSDEN. 

